The present invention relates to tote bins and more specifically to devices which enable polymeric liners to be inserted into tote bins and combination of valves and spigot systems for those.
A tote bin is a bin or storage system which holds or carries bulk product. Tote bins are generally filled with a bulk product for the purposes of storing and transporting that bulk product to an end user.
Typically, such tote bins are lined with a plastic or polymer liner which holds the bulk product. The liner has an outlet tube or spigot hermetically sealed by a membrane. The outlet spigot allows for connection to a valve so as to fill or empty the product from the liner. The valve may or may not be attached during transport.
The products which are stored and carried in tote bins typically require sanitary or sterile conditions for the filling and emptying procedures. In the case of food product sterile conditions are generally required.
To achieve a required degree of sterility all surfaces which will contact the product need to be sterilised. Thus when filling or emptying the tote bin the valve is attached in a manner so that both the valve and the membrane can be sterilised together.
One of the disadvantages of prior art tote bins which have plastic liners is that the membrane which seals the outlet spigot is arranged on the outlet spigot in such a way that it is not readily sterilisable without a risk that the membrane or its seal to the spigot will be damaged by the fluid used for sterilisation.
A typical arrangement of a prior art outlet spigot and valve is illustrated in FIGS. 1 and 2. In FIGS. 1 and 2 the outlet spigot is generally indicated by the letter xe2x80x9cAxe2x80x9d and is illustrated as being attached to a liner indicated with the letter xe2x80x9cLxe2x80x9d. The outlet spigot A has a membrane E hermetically sealed thereto.
A butterfly valve xe2x80x9cBxe2x80x9d is connected to the outlet spigot A as depicted in FIG. 2. The valve B includes a ring shaped cylindrical cutter C having a cut out segment. The cutter C is slidably located in the valve passage D, between a butterfly valve member G and the membrane E. The cutter C is a cylindrical ring with a cut out segment. When the valve B is closed the cutter C will not engage the membrane E until the valve is opened.
Once the valve B has been connected to the outlet A, and upon opening the butterfly valve member G, as illustrated in FIG. 2, the cutter C is moved to the left of the figure by an edge H of the valve member B. The edge H engages a bar J on the cutter C. The cutter C will then engage and cut the membrane E.
As the cutter C is a cylindrical ring with a cut out segment, it leaves a portion of the membrane uncut, thereby leaving a land which connects the cut portion of the membrane with the uncut. The land forms a hinge arrangement.
The arrangement illustrated in FIGS. 1 and 2 leads to several difficulties during sterilising procedures.
The first is that as soon as the valve B is opened, the membrane E is pierced by the cutter C. This means that for the arrangement of FIGS. 1 and 2 the valve components, seals and membrane cannot be sterilised through the valve.
To overcome this difficulty an additional inlet can be provided to allow the entry of a sterilising medium into the valve between the membrane E and the butterfly valve member G. In this case, prior to the opening of the butterfly valve member G, a sterilising medium is injected into the region between the butterfly valve member G and the membrane E to sterilise the membrane E, the internal portions of the outlet spigot A, the cutter C and some of the internal portions of the valve B. In this situation there will still remain the difficulty mentioned previously that the membrane or the seal between it and the outlet spigot will have the potential to be damaged.
The potential to be damaged dictates the maximum temperature and pressure at which sterilisation occurs. This in turn generally means a lower temperature and pressure sterilisation procedure will have to be used which in turn dictates that a long time will be used to achieve the necessary level of slerilisation.
One of the disadvantages of sterilising at a temperature and or pressure which is not as high as it should optionally be, is that it can take so long to complete the sterilisation process that downstream processes can be delayed.
It is an object of the present invention to provide a combination of a valve and spigot for attachment to a lined tote bin, and/or a method of sterilising and filling or emptying a lined tote bin and/or a cutter for a membrane which ameliorates, at least in part, at least one of the prior disadvantages of the prior art.
The present invention provides a tote bin liner having a liner wall to form a container, said liner wall including a transfer spigot which provides a passage from inside said liner to the outside thereof, said transfer spigot comprising:
a tubular body which defines said passage, the tubular body having an opening on the distal end thereof;
an annular surface located around the opening said annular surface providing a sealing surface adapted to engage a seal on a surface of a valve body when said valve body is assembled therewith;
a rupturable membrane sealed to said annular surface by a continuous seal around said opening, said continuous seal being located on said annular surface.
The present invention further provides a tote bin liner having a liner wall to form a container, said liner wall including a transfer spigot which provides a passage from inside said liner to a tote bin outlet, said transfer spigot adapted to have a valve mounted thereto to provide a controlled outlet from the tote bin outlet, the transfer spigot comprising:
a tubular body which defines said passage, the tubular body having an opening on the distal end therethrough;
an annular surface located around the opening;
a rupturable membrane sealed to said annular surface by a continuous seal around said opening, said continuous seal being located on said annular surface;
the tubular body being shaped and configured such that when in use and said valve is mounted to the body, a seal on the valve will clamp the membrane against the annular surface.
Preferably said annular surface is generally perpendicular to the axis of the tubular body so that a seal on a valve clamped to the body will press the membrane against the sealing surface.
Preferably the annular surface has a radially inner portion and a radially outer portion and said continuous seal is located on said radially outer portion whilst the radially inner portion is adapted to have a seal of a valve which is an engagement with the tubular body seal therewith. Alternatively the continuous seal may be located on the radially inner portion and the radially outer portion is adapted to have the seal of a valve engage therewith.
Preferably said annular surface is included on a flange of said body.
The present invention also provides a cutter assembly to cut a membrane which seals a transfer spigot on a container, said cutter assembly having:
a valve including a valve body adapted to engage with said spigot, the valve body including a valve closure member, adapted to be moved between open and closed position to open and close the valve;
at least one elongate cutter which terminates in a cutting tip, said cutting tip being adapted to rupture or slit said membrane;
actuation means for providing axial movement to said cutter within said valve body; and
said actuation means and/or said elongate cutter body being adapted to move said cutter body to cut a membrane independently of the operation of the valve closure member.
Preferably said actuation means is adapted to rotate said cutter about an axis to define an arcuate cutting action.
Preferably said cutting tip is any one of the following: a pointed spike; a blade; a crescent shaped knife; a C-shaped knife; a D-shaped cutter having an open segment.
Preferably said actuation means is adapted to move said cutter to a side of said valve closure member remote from the spigot.
Preferably said cutter is formed in at least two elongate sections, each terminating in a cutting tip, or alternatively the cutter bifurcates into two arms, each arm terminating in a cutting tip.
The cutter and actuation means may be housed in a tubular housing which is adapted to be coaxially mounted to the valve body, the actuation means in use being adapted to move the cutter through the valve body, past valve closure member when the valve closure member is open, into engagement with the membrane in cut said membrane.
The invention extends to an assembly comprising a tubular housing, cutter and actuation means for a cutter assembly according to the invention.
The invention also provides a sterilising, cutting and transfer tube wherein the tube has a cutting assembly as described in any of the paragraphs above.
The present invention provides a method of sterilising an impervious rupturable membrane attached to a tote bin spigot on a liner and subsequently filling or emptying said liner, said impervious rupturable membrane closing a passage which connects the exterior of said liner to the interior of said liner; said method comprising the steps of:
1 attaching a valve having a flow passage therethrough and a valve closure member mounted within the passage moveable between open and closed positions, the valve closure member being spaced away from the membrane;
2 passing a sterilising medium into at least the space between said membrane and the valve closure member to sterilise the outside surface of said membrane and that part of the internal flow passage within said valve between said membrane and the valve closure member;
3 piercing said membrane with a cutter which passes along the flow passage past the valve closure member when the valve closure member is in the open position.
Preferably said valve closure member is in an open position at the start of and for the duration of step 2.
Preferably said sterilising medium sterilises the whole of the internal flow passage within said valve.
Preferably said valve is of the butterfly type.
Preferably said cutter is linked to a rotatory actuator to rotate said cutters.
Preferably the cutter is one of the types described in preceding paragraphs.